Secretary of State Hillary Clinton apologized for the "for the losses suffered by the Pakistani military" during a NATO airstrike that killed 24 Pakistani troops.

When announcing the apology, the AP reports, Clinton also said that Pakistan was reopening a crucial military supply line into Afghanistan. Pakistan had closed its border to the coalition forces since the attack in November.

The road to this resolution has been fraught with conflict. In a lot of ways, it came to a head at the NATO summit in Chicago in May. President Obama and Pakistani President Asif Ali Zardari were not able to hammer out a deal to reopen the supply line.

In June, Secretary of Defense Leon Panetta made uncharacteristically candid comments about the relationship between the countries.

As we reported, Panetta said that American officials were "reaching the limits of our patience" with Pakistan "because that nation continues to allow terrorists to use its territory 'as a safety net in order to conduct ... attacks on our forces.'"

"I once again reiterated our deepest regrets for the tragic incident in Salala last November," Clinton said. "I offered our sincere condolences to the families of the Pakistani soldiers who lost their lives. Foreign Minister Khar and I acknowledged the mistakes that resulted in the loss of Pakistani military lives. We are sorry for the losses suffered by the Pakistani military."

She said Pakistan's decision to reopen the ground supply lines into Afghanistan show "Pakistan's support for a secure, peaceful, and prosperous Afghanistan and our shared objectives in the region."

"'The continued closure of supply lines not only impinge(s) on our relationship with the US, but also on our relations with the 49 other member states of Nato/Isaf,' Prime Minister Raja Pervez Ashraf told senior government and military officials, according a statement issued by his office."

Update at 12:44 p.m. ET. A Bit Of Background:

Just how difficult has this issue been for the two countries? Basically, in different government reports, they have disagreed on just what happened in that November airstrike.